Battery Tender/Maintainer?
Thread Starter
Junior Member
Joined: Oct 2015
Posts: 19
Likes: 0
From: Olathe, KS
Car: 1991 Pontiac Firebird
Engine: 3.1L V6
Battery Tender/Maintainer?
Does anyone use a battery tender or maintainer when your car is in storage (for the winter, etc)?
Any issues, pros, cons?
Any preferred brands or anything to avoid?
Thank you!
Any issues, pros, cons?
Any preferred brands or anything to avoid?
Thank you!
Joined: Feb 2001
Posts: 8,494
Likes: 411
From: Sophia, NC
Car: 2016 Camaro SS + 1986 Z28
Re: Battery Tender/Maintainer?
I bought this "Battery Minder Plus" a few years back, and the unit itself has given me no trouble. It ain't quick, but it'll charge a dead battery, and it keeps a battery fully charged with no issues at all in the cold garage.
http://www.northerntool.com/shop/too...2201_200332201
...it DID teach me a lesson though. AGM (Optima) batteries CAN be OVER charged to where it will no longer HOLD a charge. That's why their charges are so pricey. They detect when the battery is full and will shut off. My traditional "GOLD" whatever battery can handle constant charging, but the pricier AGM batteries CAN NOT!
Ask me how i know, lol. ....my Optima got to the point where it would read 12.75 or so right after running, or while on the battery minder, then within an hour, be down to 12 or so. ....it would start ok, but if I ever needed to move it around the driveway, or cranked it up for people to hear at a show, I'd run the risk of not getting that second start! Basically I had ONE start, then it needed charging. ...and it tested at the parts store as bad. After further reading, I've found that someone who KNOWS AGM batteries can sometimes drain, and recharge, and get them working...but I had already replaced mine. Oh well. Lesson learned.
http://www.northerntool.com/shop/too...2201_200332201
...it DID teach me a lesson though. AGM (Optima) batteries CAN be OVER charged to where it will no longer HOLD a charge. That's why their charges are so pricey. They detect when the battery is full and will shut off. My traditional "GOLD" whatever battery can handle constant charging, but the pricier AGM batteries CAN NOT!
Ask me how i know, lol. ....my Optima got to the point where it would read 12.75 or so right after running, or while on the battery minder, then within an hour, be down to 12 or so. ....it would start ok, but if I ever needed to move it around the driveway, or cranked it up for people to hear at a show, I'd run the risk of not getting that second start! Basically I had ONE start, then it needed charging. ...and it tested at the parts store as bad. After further reading, I've found that someone who KNOWS AGM batteries can sometimes drain, and recharge, and get them working...but I had already replaced mine. Oh well. Lesson learned.
Last edited by Abubaca; Feb 5, 2017 at 06:54 PM.
Thread Starter
Junior Member
Joined: Oct 2015
Posts: 19
Likes: 0
From: Olathe, KS
Car: 1991 Pontiac Firebird
Engine: 3.1L V6
Re: Battery Tender/Maintainer?
I bought this "Battery Minder Plus" a few years back, and the unit itself has given me no trouble. It ain't quick, but it'll charge a dead battery, and it keeps a battery fully charged with no issues at all in the cold garage.
http://www.northerntool.com/shop/too...2201_200332201
...it DID teach me a lesson though. AGM (Optima) batteries CAN be OVER charged to where it will no longer HOLD a charge. That's why their charges are so pricey. They detect when the battery is full and will shut off. My traditional "GOLD" whatever battery can handle constant charging, but the pricier AGM batteries CAN NOT!
Ask me how i know, lol. ....my Optima got to the point where it would read 12.75 or so right after running, or while on the battery minder, then within an hour, be down to 12 or so. ....it would start ok, but if I ever needed to move it around the driveway, or cranked it up for people to hear at a show, I'd run the risk of not getting that second start! Basically I had ONE start, then it needed charging. ...and it tested at the parts store as bad. After further reading, I've found that someone who KNOWS AGM batteries can sometimes drain, and recharge, and get them working...but I had already replaced mine. Oh well. Lesson learned.
http://www.northerntool.com/shop/too...2201_200332201
...it DID teach me a lesson though. AGM (Optima) batteries CAN be OVER charged to where it will no longer HOLD a charge. That's why their charges are so pricey. They detect when the battery is full and will shut off. My traditional "GOLD" whatever battery can handle constant charging, but the pricier AGM batteries CAN NOT!
Ask me how i know, lol. ....my Optima got to the point where it would read 12.75 or so right after running, or while on the battery minder, then within an hour, be down to 12 or so. ....it would start ok, but if I ever needed to move it around the driveway, or cranked it up for people to hear at a show, I'd run the risk of not getting that second start! Basically I had ONE start, then it needed charging. ...and it tested at the parts store as bad. After further reading, I've found that someone who KNOWS AGM batteries can sometimes drain, and recharge, and get them working...but I had already replaced mine. Oh well. Lesson learned.
Re: Battery Tender/Maintainer?
http://www.harborfreight.com/12-volt...ger-62813.html
Cant beat it they work great have three... If you have a store near you and a smart phone you can get 20% off that @ 16.99
Cant beat it they work great have three... If you have a store near you and a smart phone you can get 20% off that @ 16.99
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Re: Battery Tender/Maintainer?
Out of four Battery Tender's, only one still works. Last one was only a year or two old when it died. They offer a warranty, but by the time you pay postage you might as well just buy a new one... Except the new ones are crap too.
I'd trust the HF model before I bought another Battery Tender brand.
I'd trust the HF model before I bought another Battery Tender brand.
On Probation


Joined: Apr 2007
Posts: 1,592
Likes: 18
From: Syracuse NY
Car: 84 Z-28
Engine: 305 HO
Transmission: r-700
Axle/Gears: 3:73
Re: Battery Tender/Maintainer?
On my Goat, Z and Triumph I just disconnect the battery for their winter sleep!
No battery tender etc.
In spring I just hook up the battery and fire them up!
If your battery is crap or old it won't hold a good charge..............
No battery tender etc.
In spring I just hook up the battery and fire them up!
If your battery is crap or old it won't hold a good charge..............
Joined: Apr 2000
Posts: 3,938
Likes: 99
From: Huntsville AL
Car: 88GTA
Engine: 5.7TPI
Transmission: Auto
Axle/Gears: 3.27
Re: Battery Tender/Maintainer?
I been using this 4 pack for 2+ years. Works great.<br/>Also use a 2 pack with no issues
Joined: Mar 2001
Posts: 10,402
Likes: 2,081
Car: '89 Firebird
Engine: 7.0L
Transmission: T56
Re: Battery Tender/Maintainer?
Battery tender is a good idea. I don't have one so I have been breaking out the battery charger once a month until driving season again.
It is smart to charge at low current (like a tender does). Different chemicals form on the plates when the battery charges and discharges. There is a huge change of volume of those chemicals and it can actually cause the material on the plate to break away. The slow charge of a tender helps to limit damage from volume expansion.
AGM batteries require different charging voltage than a flooded lead acid battery. If you use a normal charger (for flooded lead acid) then it will slightly overcharge the AGM battery and drive off the water until the battery fails. There isn't much water in an AGM so not very tolerant to over charging.
It is smart to charge at low current (like a tender does). Different chemicals form on the plates when the battery charges and discharges. There is a huge change of volume of those chemicals and it can actually cause the material on the plate to break away. The slow charge of a tender helps to limit damage from volume expansion.
AGM batteries require different charging voltage than a flooded lead acid battery. If you use a normal charger (for flooded lead acid) then it will slightly overcharge the AGM battery and drive off the water until the battery fails. There isn't much water in an AGM so not very tolerant to over charging.
Supreme Member




Joined: Jan 2000
Posts: 3,178
Likes: 48
From: Tracy, CA
Car: '87 IROC
Engine: LB9
Transmission: TH700R4
Re: Battery Tender/Maintainer?
I have three old style (no temperature compensation) BatteryMINDer's currently in use. If the car isn't going to be moved in 3-7 days, I hook them up.
I have the Camaro battery hard wired with the two-wire trailer connector that came with the maintainer.

The battery in the photo is over 16 years old. Still cranks with authority.

With BatteryMINDer brand, all pros, no cons here. I used to hear of stories of Battery Tender brands burning out after a few years, but this is old news....
Buy a maintainer and use it!
I have the Camaro battery hard wired with the two-wire trailer connector that came with the maintainer.

The battery in the photo is over 16 years old. Still cranks with authority.

With BatteryMINDer brand, all pros, no cons here. I used to hear of stories of Battery Tender brands burning out after a few years, but this is old news....
Buy a maintainer and use it!
Joined: Dec 2000
Posts: 1,954
Likes: 65
From: NC
Car: 1987 Iroc
Engine: 357 Single plane and a Ysi vortech
Transmission: T56
Axle/Gears: 3.50 9"
Re: Battery Tender/Maintainer?
I've tried 3-4 different brands and I've good luck with all of them. The main thing is to get one and use it!
Supreme Member




Joined: Oct 2004
Posts: 4,526
Likes: 238
From: Henrietta NY
Car: 1984 Trans Am L69
Engine: Sniper EFI Powered 355
Transmission: WC T5 w/ Steel Support Plate
Axle/Gears: 3.42 10 Bolt Posi
Re: Battery Tender/Maintainer?
I have one of these on all 3 of my motorcycles, trans am and tractor battery. Been using the same ones for years and no issues. Without my EFI bike and TA always have battery issues in the spring.
http://www.harborfreight.com/automat...ger-42292.html
Code:
http://www.harborfreight.com/automatic-battery-float-charger-42292.html
Last edited by midias; Feb 9, 2017 at 08:03 AM.
Supreme Member
Joined: Apr 2006
Posts: 4,482
Likes: 9
From: Northern, CA
Car: 1989 Iroc-Z Camaro
Engine: TBI,5.0
Transmission: Automatic 700R4
Axle/Gears: Eaton Posi,3.42,LPW Ultimate Cover
Re: Battery Tender/Maintainer?
My Neighbor has the "Harbor Freight" one on his "74" Shovel Head Harley.
Works great.
Works great.
Senior Member
iTrader: (2)
Joined: Mar 2014
Posts: 728
Likes: 51
From: South Texas
Car: '89 Iroc Z28-15,100 Original Miles
Engine: 350 TPI
Transmission: 700R4
Axle/Gears: Limited Slip, 2.77 Ratio
Re: Battery Tender/Maintainer?
Wife bought this one for my C6 a few years ago and I use it year round on the IROC. I like that I don't have to go under the hood to hook up or disconnect. Just pop it in my cig lighter and close the door. I have several of the Schumacher Walmart $20 tenders that I use on my other cars and they work just as well.
Joined: Jun 2003
Posts: 5,028
Likes: 78
From: Desert
Car: 1991 Z28 Vert
Engine: 383 single plane efi
Transmission: T-56
Axle/Gears: 8.8 with 3.73s
Re: Battery Tender/Maintainer?
I've used the Schumacher maintainer that has the float mode for several years now. No complaints. Been hooked up to my Optima red top. Although I can drive the car year round it only gets driven every 2-3 weeks and it's trips are usually pretty short (10-15 miles round trip) which might prevent the alternator from fully charging the battery.






